I am having the same issue described here: https://our.umbraco.org/projects/collaboration/merchello/merchello/77468-unable-to-upgrade-to-200201
The only thing I have to add is that I got this error immediately when attempting to install the 2.1 package (https://our.umbraco.org/FileDownload?id=16322) through the umbraco dashboard. After cleaning/rebuilding the solution, I get this error on any page I visit.
The only help I saw in the above forum post was to set the merchelloConfigurationStatus setting to "1.14.1" so as to retrigger the upgrade, however my merchelloConfigurationStatus was already (unchanged) set to 1.14.1.
Any ideas?
Exception is: Invalid column name 'author'. Invalid column name 'internalOnly'.
